Floating pin mandrel



A. KA'rz FLOATING PIN MANDR'EL Filed May s, 1945 Katz I Aug, 15;,1944.

Hte/n ez/s. 4

Patented Avug.l5, 1944 jz,3ss,734

Albert Katz, Detroit, Mich.. aligner to. Bundy Tubingr Company, Detroit,Mich., a corporation of Michigan Application May 6,1943, seriamente 10Claims.

ratus which had a mandrel heldin drawing posi- 5 tion by a tension rod.Where -a tension rod is used the tube to be drawn has to be threadedover the mandrel and the tension rod and this is an unhandy andtime-consuming procedure, particularly where long lengths of tube arehandled. 10

The floating pin is merely inserted into the leading end of the tube,the leading end is swaged,

then the leading endl of the tube is passed into the die and as the tubeis drawn the floating mandrel orh pin"isvmoved ,into and held in- `1lidrawing position by friction.

However, some difiicult problem present themselves in the use oftheeiloating pin in that it is liable to set u'p a chattering action.This chattering action results in longitudinal vibra- 2Q tions. The pinis pulledtightlyinto position. by the drawing section on theleading endof the tube thus Vincreasing the frictionto the point where the forcesovercome friction allowing the pin to shift or jump back away fromthedie so g5 that it is again picked up by. frictionl and moved tightlyinto drawing position resulting in longitudinal chatter. -'Moreover, thewear on the v floating pin is such that heretofore the pins have had arelatively short-life, particularly where a 30 single drawing actionaccomplished. relatively great or severe 'draw or reduction.

It is the object of the ffpresent`inventionto provide an improved tubedrawing device, and

animproved floating mandrel or pin, particu- 35 larly for use in makinga heavy draw o'na tube.

wherein chatter is eliminated 0r at least the possibilities of chatterare minimized, and wherein the useful life ofthe pin is greatlyincreased. i An apparatus and a floating mandrel for car- 40 rying outthe invention are in the accompanying drawing. f y

Fig. 1 is a cross-sectional view of a tube. a die and a floating pinshowing the parts in position preparatory to the commencement of adrawing action.

' Fig. 2 is a sectional view illustrating thedrawing in progress.

Fig. 3 is a side elevational view somewhat enlarged showing the improvedpin.

Fig. 4 is' a sectional view taken substantially on line I -l of Fig. 3.

I'he die, as illustrated, embodies suitable materials, and it has a bodyi formed with a die pasfat 2l.

(ci. 20s- Jn to provide a suitable entrance angle 2; an intermediateportion has a `working angie I; to the rear of the working portion is aland l the walls of which preferably substantially parallel the axis;the outlet of the passage preferably has a relief angle shown at 5. Atthe intersections of these angles the surfaces are suitably blended toeliminate sharp corners. The movement of the tube through the die isfrom left to right, as the drawing is viewed. A

The floating pin is generally illustrated at Il and to start the drawingaction the pin is.in

' serted in the leading end of the tube, as shown in Fig. -1. The tube,of course, may be of any length. To the rear of the pin within the tubeis placed a quantity of lubricant, illustrated at i l.

The lubricant is preferably in the nature of grease, as distinguishedfrom a fluid oil, although it should not be toc viscous. After themandrel is thus inserted, the leading end of the tube is vreduced orswa'ged by a suitableswaging tool,

as illustrated at l2, so that this end of the tube may be passed throughthe die and gripped by a suitable pulling device (not shown). Y

The pin structure is shown in Figs. 3 and 4.

At one en d it has a land section I6 of cylindrical form designed to fitin the land section 4 of the die with the desired clearance. Extendingfrom the land section is a tapered portion which may be termed the pinangle, as shown at It. This is the working portion o f the mandrel. Abody portion i1 lies next adjacent the working portion. Extending fromthe body I1 is a tail piece Il of slightly smaller diameter than thebody. The body preferably fairly well ts the interior of the tube to bedrawn. V

InV the face of the working angle it one or more areas of depression areprovided, as shown These'areasmaybe formed by iiats or relieved surfacesformed in themaxidrel.v As indicated in Fig. 4, there may be four ofsuch flats equally spaced throughout the circumference, althoughthis'number may be varied toV meet variable conditions. .'Ihese datsextend substantially from the Vline of juncture betweenthewcrkingangleandtheland ilbutdonot extend throughout thewhole linealextent of the working angle.' but to the contrary, terminate in anintermediate portion of the working angle,

I0 as illustrated-at Il. At the juncture of the working angle and theland there is an undercut 22 and the flats are formed in the-.workingangle so as to extend into communication with the undercut.Inthcpinshowmtheangleofthe sage therein. Theentranceopeningiashaoedllworkingpartllisifromtheaxisofthepin,

and the surfaces 2l are 12 30' from the axis.

When the deviceisinusethepartstakeaposition as illustrated in Fig. 2.The tube is being pulled through the die from left to right and thefloating mandrel is pulled into drawing position with respect to the dieand held in this position by friction. The lubricant plays a part inthis function. It should be viscous enough to provide the desiredfriction. If it is too viscous the-pin might be held in position by toomuch pressure. On the other hand, if the lubricant is too thin it mayfail to push the pin into place. An example of a satisfactory lubricantis a commercially ob'- tainable lubricant known as Penola No. 5214,which may in some instances be vmixed four parts of Penola to/one partof tallow.

In the drawing action, the metal of the tube wall first contacts theentrance angle 2 of the die. 'I'he tube is ensmalled as it moves throughthe die betweenv the working angles 3 of the die and II of the pin,while the drawn tube is sized as to external and internal diameters andas to wall on those portions of the land immediately forward of the ats.

I'claim:

1. A floating mandrel for use with a die for drawing tube, comprising abody portion having a diameter approximating the'internal diameter ofthe tube to be drawn, a tapered portion exthickness by the land l of thedie and landl body" of the mandrelv dts freely within the tube so thatan adequate supply of lubricant passes the body and reaches the workingangle of the mandi-e Some of the lubricant squeezes in betending fromthe body portion and having its small diameter remote from the bodyportion, a

land portion extending from the small end of the tapered portion andhaving a diameter less than that of the body portion for sizing theensmalled tube, and one or more areas of depression in the surfaces ofthe tapered portion extending substantially from the small end thereof adistance less than the axial dimension of the tapered portion.

2. A oating mandrel for use with a die for drawing tube, comprising abody portion having a cross dimension approximating the internal crossdimension of the tube to be drawn, a tapered portion extending from thebody portion and having its small cross dimension remote from the bodyportion, a land portion extending from the small end of -the taperedportion and having a cross dimension less than that of the body portionfor sizing the ensmalled tube, and

` one or more areas of depression in the surfaces tween the tube and theworking faces of the mandrel angle, and flows into the spaces or areasprovided by the ats. In as much as the flats.

communicate with the. undercut, the lubricant flows into the undercutand may accumulate into a complete annulus of lubricant at the undercut.

of the tapered portion extending substantially from the small endthereof a distanceless than the axial dimension of the tapered portion.

3. A oating mandrel foruse with a die-for drawing tube, comprising abody portion having a diameter approximating the internal diameter ofthe tube to be drawn, a tapered portion extending from the bodyportion-and having its small diameter remote from theA body portion, aland portion extending from the small end of the tapered portion andhaving a diameter less than The lubricant is drawn from this point overthe I land 0f the mandrel.

at the same time provides lubrication, thus promoting longer life forthe mandrel.

One part of the mandrel which is subjectedl to the areas of depressionor flats are too extreme,

y As mentioned above, this-l reduces the friction and eliminates chatterand the metal of the tube flows into the depressions thus providinglocalized thickening o f the metal. This requires heavier drawing actionon those f portions of the land immediately forward of the flats, andthis localized thickening of metal ref suits in a relatively rapid wearof the land. This situation is liabl to occur if the ilats depressionsextend throughout the axial' dimension of the'tapered working portion.However; by theexpedient `of providing the dats for only a portion ofthe axialzextent of the angular working face the localized thickening ofthe metal of the tube is minimized and yet an adequate supply oflubricant is provided eventhough the lubricant must essentially squeezein between the angular'worki'ng face of the mandrel and the inner wallof the tube. The metal of the tube may thicken somewhat into the,underc, but there is enough free space for some of the lubricant to ilowinto the undercut and form an annulus so that the land may be lubricatedthroughout its circumferential extent. Moreover, what localizedthickening occurs at the flat is in a measure or areas of oifiset by therelatively largesuppiy of lubricant 'l5 that of the body portion for-sizing the ensmalled tube, one or more4 areas of depression in thesurfaces of the tapered portionextending substantially from the smallend thereof a distance less than the axial dimension of the taperedportion, and an undercut formation substantially at the juncture of theland and the tapered portion which which the one or more areas ofdepression communicate.

f 4. A floating mandrel for use with a die for drawing tube, comprisinga body portion having a diameter approximating theinternal diameter .ofthe tube to be drawn, a tapered portion extending from the body portionand having its small diameter remote from the body portion, a landportion extending from thesmall end of the tapered portion and having adiameter less than that of the body portion for sizing the ensmalledtube, one or more areas of depression in the surfaces of the taperedportion extending substantially from the small end thereof a distanceless than the axial dimension of the tapered portion, and acircumferential undercut formation substantially at the juncture of theland and tapered portion with which the one or more areas of depressioncommunicate.

5. A Ifloating mandrel for use with a die for drawing tube, comprisinga. body portion having f land portion extending from the small end ofthe tapered portion and having a diameter less than that of the bodyportion for sizing the ensmalled tube,one or more substantially fiatareas in the surface of the tapered portion extending substantially fromthe juncture of the tapered portion and the land portion to anintermediate location between the junctures of the tapered portion withthe body portion and the land portion, said substantially fiat areashaving an angularity relative to the axis somewhat greater than thatofthe tapered portion.

6. A floating mandrel for use with a die for drawing tube, comprising abody portion having a diameter approximating the internal diameter lofthe tube to be drawn, a tapered portion extending from thebod'yportion and having its end4 of small diameter remote from the bodyportion, a land portion extending from the small end of the taperedportion and having a diameter less than that of the body portion forsizing the ensmalled tube, one or more substantially fiat areas in thesurface of the tapered portion extending s'ubstantially from thejuncture of the tapered portion and the land portion to an intermediatelocation between the junctures of the tapered porportion and the landportion forming a groove tion with the body portion and the landportion,

said substantially :dat areas having an angularity relative to the axissomewhat greater` than that of the tapered portion, and acircumferential undercut at the juncture between the tapered portion andthe land portion with which the substantially fiat surfaces communicate.

'7. A tube drawing device, comprising a die with a die passage for ,themovement of tube there y through, said die passage having an entranceopening with interior surfaces at an angle to the axis, an intermediateworking section with interior surfaces at an angle to the axis less thanthe angle'of the surfaces o'f the entrance opening, and a land sectionadjacent the .outlet and having surfaces substantially paralleling theaxis, a Boating mandrel for disposition within a -tube to be movedthrough the passage, said mandrel having a body portion whichsubstantially fits within the tube, an intermediate tapered workingportion for cooperation with the working section of the die, a landportion of 'cylindrical form for pro-- in communication with the areasof depression.

9. A tube drawing device, comprising a die with a die passage for themovement of tube therethrough, said die passage having an entranceopening with interior surfaces at an angle to the axis, an intermediateworking section with interior surfaces at an angle to the axis less thanthe angle of the surfaces of the entrance opening, and aland sectionadjacent the outlet end having surfaces substantially paralleling theaxis, a oating mandrel for disposition within atube to be moved throughthe passage, said mandrel having a body portion which substantiallyfits.

within the tube, an intermediate tapered working portion for cooperationwith the working section of the die, a land portion of cylindrical formfor projection into and cooperationV with the land section of the die,circumferentially spaced substantially at areas on the working portionextending from an intermediate'part of the work-Q ing portion tothejuncture between the working portion and the land portion at an anglegreater than the angularity of the tapered working portion, and anundercut formation providing a circumferential groove at the juncturebetween the working portion and the lland portion and which is incommunication with the substantially fiat areas; i

:lection into and cooperation with the land section of the die. andareas of depression in the working portion of mandrel extending from anintermediate part of the working portion to the juncture between theworking portion and the paralleling the axis, a floating mandrel fordisposition within a tube to be moved throughl a passage, saidmandrelhaving a body portion which 10. A tube drawing device, comprising a dieI.with a die passage for the movement of tube therethrough, said diepassage having an entrance opening, a. working section with interiorsurfaces at an angle to the axis and a land sectionhadjacent the outlethaving surfaces substantially paralleling the axis, a oating mandrel fordisposition within a tube to be moved through the passage, said mandrelhaving a body portion which substantially fits within the tube, anintermediate tapered working portion for cooperation with the workingsection of the die, a. land portion for projection into and cooperationwith the land section of the die, and areas of depression in the workingportion of the mandrel extending from an intermediate part of theworking portion to the juncture between the working pori tion and theland portion.

' ALBERT KATZ.

